Australia has entered spring under an ominous sign: temperatures across the country's east coast have surged to levels not seen this early in the season for more than a century and a half, bringing extreme fire danger, powerful winds, and flooding to different parts of the continent simultaneously.

Sydney, Australia's most populous city with 5.6 million residents, recorded temperatures approaching 33°C on Saturday 6 September — nearly 13 degrees above the September average — in what meteorologists say is likely the hottest start to spring since the city's Observatory Hill weather station opened in 1858. At Sydney Airport, the thermometer already read 28.6°C by mid-morning. For the first five days of September, Sydney is on track to average a daily maximum of 27°C, matching its typical midsummer figure. Brisbane and other parts of southern Queensland saw temperatures peak in the mid-30s under similarly unseasonable conditions. Authorities responded by declaring a total fire ban across greater Sydney, where fire danger was rated "extreme" — the second-highest category — as gusty north-westerly winds blowing down from Australia's northern interior drove rapid drying of vegetation.

The dramatic conditions are being shaped by a strengthening El Niño weather pattern in the Pacific, which the United Nations weather agency warned on Thursday was continuing to intensify and could persist until early 2027. El Niño events typically bring hotter and drier conditions to southern and eastern Australia during winter and spring, elevating the risk of heatwaves, drought, and bushfires. Meteorologists say spring 2025 temperatures across the region could average as much as three degrees above recent decades' baseline, potentially making it the hottest spring on record. Australia's national fire and emergency services council has already flagged heightened bushfire risk across northern and south-eastern New South Wales, south-east Queensland, north-eastern Tasmania, and parts of Western Australia, South Australia, Victoria, and the Northern Territory.

The weather picture across the continent is strikingly contradictory. While coastal New South Wales sweltered, snow was falling in Thredbo in the Snowy Mountains of southern NSW — though forecasters noted that Australia's snowpack is at a historic low for early September, even at the highest elevations, meaning the fresh snow will have little lasting impact on ski conditions. Heavy rain and minor flooding were forecast for north-eastern Victoria and northern Tasmania, whose catchments remain saturated after multiple flood events over winter. Wind gusts of up to 110 km/h were possible in South Australia's Mount Lofty and Flinders ranges.

Climate scientists and emergency authorities warn that extreme heat and fire weather are becoming more frequent in Australia as a result of climate change. The country experienced devastating bushfire seasons in recent years, and the current conditions — an early spring heatwave compounded by a powerful El Niño — suggest the 2025–26 fire season could be particularly challenging. Authorities are urging residents in fire-prone areas to prepare now and follow official guidance as conditions are expected to remain warm, dry, and dangerous well into the coming months.